(I didn't want to make yet another thread about DRKs and since i'm also confused about some things, i thought i'd just post here)

I'm a DRK 60, ilvl 180, vit accessories, leveled through dungeons fine without much problem with aggro, mana management and such.
The other day i was tanking high level roulette and got Stone Vigil HM. Since i'm used to do this as WAR (my main) and the healer (SCH) was my husband who i trust and plays literally by my side, i decided to pull the entire first section up to that arena with the big Watch Wyvern and some little Dragonfly Hunters.

Thing is: my HP dropped really fast and and we end up dead before a single mob died before us. The dps were black mage and bard, got them from queue, didn't check their gear before the pull, but i don't think it would make much of a difference because of how quick i died. The mobs were hitting like 10, 20% my hp each.

Had grit, darkside and blood price on and popped some defensive cooldowns (don't remember which ones, honestly, because it was just a simple routine thing we all do automatically).
Other examples i can give are Tamtara HM first section, Snowcloak, Amdapor Keep HM... I can keep up fine with big pulls like these as a Warrior, but as DRK i have to do lesser pulls or things don't go so well.

Anyone have experience with big pulls like these as a Dark Knight? Am I missing something, it's a balance problem or it's just how the job is supposed to be?